Hitachi, Ltd.

Hitachi Denshi Kabushiki Kaisha

Kunihiro Hamada

Yutaka Chiba

Mitsutaka Hikita

Yoshio Abe

Atsushi Sumioka

Yoshikatu Ishida

A transmitter circuit useful for example, in a portable radio-telephone comprises a power amplifying circuit which includes a driving amplifier constituted by a Si-MOSFET element and a power amplifier constituted by a GaAs-FET element. The gate voltage control is performed simultaneously for the driving amplifier and the power amplifier. By virtue of this mixed arrangement, a transmitting power amplifying circuit having a high power conversion efficiency is realized inexpensively.

Transmitter circuit

In order to reduce the size of a duplex radio communication transceiver such as a mobile telephone, this transceiver is constructed of a transmitting and receiving duplexer, a filter to be coupled to the duplexer, an amplifier for amplifying a signal received, and a filter to be connected with the output of the amplifier. All the filters are made of acoustic surface wave filters, and all the circuits are mounted on a single metallic substrate and sealed by means of a metallic casing into a module. The transceiver thus constructed has a volume which is one tenth as small as that of the device of the same kind according to the prior art.

Duplex radio communication transceiver

Growing community of inventors

Koganei, Japan

Kunihiro Hamada